The present invention relates to a tap which is adjustable in relation to the tanks of filling machines having a medium or small capacity and being of the automatic type and suitable to fill bottles, jars or cans with liquids of various density, such as foodstuff for instance.
The industrial-type filling machines usually include a tank which is normally cylindrical and contains the liquid to be transferred into the containers; said tank is equipped with a series of taps arranged around the cylinder and under each one of the them are arranged the containers to be filled, which are conveyed to the tank by a conveyor belt and are arranged on a turning platform having a vertical movement which brings the containers in touch with the taps.
The known taps used in the above-mentioned tanks are of the fixed type in relation to the tank and they consist essentially of a pipe in which another pipe, having a smaller diameter and ending with a shaped cap, is axially inserted; the liquid passes from the tank into the cylindrical chamber formed by the inside wall of the external pipe and the outside wall of the smaller pipe being inserted inside, while the air being present in the container exits through the internal pipe and this happens either because of the atmospheric pressure or because of suction in the installations with a high hourly performmance.
The contact between the terminal part of the tap and the container causes the opening of the tap due to the upward sliding of the external part of the tap. While the excursion of the platform which carries the containers to be filled is usually fixed and is only sufficient to insert the terminal part of the containers in the taps, the tank equipped with the taps having a fixed protrusion must be brought to the right level with reference to the height of the containers which are being filled. For this reason it is necessary that the tank be equipped with a mechanical device suitable for the lifting and the lowering.
In the filling machines having a medium or small capacity, the need to lift or to lower the tank involves remarkable complication in the construction which is reflected in a noticeable increase in the cost of the machine. Besides, in the case of filling machines having an atmospheric pressure tank with fixed taps, since the filling speed depends on the level difference between the free space resulting from the upper surface in the tank and the level of the container, such speed remains constant because the level in the tank is usually kept constant. It follows that in the atmospheric pressure tanks having fixed taps, the filling speed cannot, therefore, be increased.